1. Field of the Invention
The present invention relates to an electrode for a plasma display panel (PDP) in which an electrode having high adhesive power is formed on a glass substrate of a color plasma display panel and a method for forming the same.
2. Discussion of the Related Art
FIG. 1 is a cross-sectional view showing a structure of a conventional PDP.
First, a pair of upper electrodes are formed on a front glass substrate 1, as shown in FIG. 1. Next, a dielectric layer 2 is formed over the pair of the upper electrodes 4 by employing a printing method and a protecting layer 3 is formed on the dielectric layer 2 by a deposition method. The pair of upper electrodes 4, the dielectric layer 2 and the protecting layer 3 constitute the upper structure.
Secondly, on a back glass substrate 11, there is formed a lower electrode 12. Sidewalls 6 are formed in order to prevent crosstalk between the cell and an adjacent cell. Luminescent materials 8, 9 and 10 are formed on both sides of each of the sidewalls and on the back glass substrate 11. The lower electrode 12, the sidewalls 6, and the luminescent materials 8, 9, and 10 constitute the lower structure. A non-active gas fills the space between the upper electrode 4 and the lower electrode 12 such that a discharge region 5 is formed.
The operation of a general PDP will be explained.
Referring to FIG. 1, a driving voltage is applied to the pair of upper electrodes so that a surface discharge is generated in the discharge region 5, thereby generating ultraviolet light 7. The ultraviolet light 7 excites the luminescent materials 8, 9 and 10, thusachieving color display. In other words, the space charge which is present in the discharge cell moves to the cathode due to the driving voltage. The space charge collides with non-active mixed gas which is a penning mixed gas added to by xenon (Xe), neon (Ne) and (He) helium (which is the main component of the mixed gas), such that the non-active gas is excited and ultraviolet light 7 of 147 nm is thus generated. Herein, when the non-active gas fills the discharge cell, its pressure is 400-500 torr.
The ultraviolet light collides with the luminescent material 8, 9 and 10 on the sidewalls 6 and the back glass substrate 11, thus forming a visible ray region.
A conventional electrode of a PDP and a method for forming the same will be discussed with the accompanying drawings.
FIGS. 2a and 2b are cross-sectional views showing upper and lower substrates of a PDP according to a conventional method.
As shown in FIG. 2a, for the lower substrate, a metal conductive material 30 such as nickel (Ni) or aluminum (Al) is formed on a back glass subtrate 11 (dielectric substrate) by means of a printing technique. As shown in FIG. 2b, for the upper substrate, copper (Cu) 35 used as an electrode is formed in a front glass substrate (dielectric substrate) (1).
Cu, Ni, and Al have all a very low interfacial with respect to glass. Thus, a chromium (Cr) layer 40 is formed between the glass surface and Cu 35, or between the glass surface and Al 30 or Ni in order to maintain adhesion between the glass and the Cu 35, or between the glass surface and the Al 30 or the Ni.
Referring to the forming process, a Cr thin film 40 is formed on the front glass substrate 1 of the PDP by means of a sputtering method in order to improve the interfacial coherence. Then a Cu film (35) used as an electrode is formed on the Cr thin film 40. Next, another Cr thin film 40 is formed on the Cu film 35 in the same sputtering method in order to improve the interfacial coherence. Finally, employing annealing, a glass is used to cover the entire surface of the front glass substrate 1 inclusive of the Cu film 35 and the Cr thin films 40.
Like the glass substrate, a dielectric substrate is applied in the same manner as the glass substrate. Similarly, in the same manner, the electrode on the front glass substrate 11 shown in FIG. 2a is formed.
A conventional electrode of a PDP and a forming method thereof have the following disadvantages.
Since Cr is a pure metal, Cr has a poor interfacial coherence with respect to glass. Besides, in case glass is annealed at a high temperature, interfacial cracks or foam are generated at the interface of the glass and the Cr due to their different rates of expansion, and thus the discharge of the PDP becomes unstable and the life span of the PDP becomes shortened. Moreover, since the coupling is made between two different metals (Cu and Cr) that is, an electrode and an interfacial adhesives a sputtering process is carried out for the Cu and a separate sputtering process is carried out for the Cr. Accordingly, the overall process is complicated.
Therefore, the present invention is directed to an electrode of a plasma display panel (PDP) that substantially obviates one or more problems due to limitations and disadvantages of the related art.
An object of the invention is to provide an electrode of a plasma display panel (PDP) in which, on a glass substrate of a color plasma display panel, there is formed an electrode having a high adhesive power for improving a discharge condition of a PDP and its life span and a forming method thereof.
Additional features and advantages of the invention will be apparent from the description which follows and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, the electrode of a PDP in which a metal electrode is formed on a dielectric substrate includes a metal ceramic thin film formed between the metal electrode and the dielectric substrate or a glass substrate.
In another aspect, a method for forming an electrode of a PDP in which a dielectric substrate and a metal electrode are formed includes the steps of forming a metal ceramic thin film on a predetermined portion of the dielectric substrate; and forming an electrode having the same metal element as the metal ceramic thin film on the metal ceramic thin film.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.